A variety of pruning shears are known and commonly used in cutting and trimming plants and trees, such as U.S. Pat. Nos. 4,073,059 and 5,743,018. While these devices are useful to remove unwanted growth, they do not operate to prevent future growth on or near the plant or tree, and thus require the user to monitor the area and return to cut additional unwanted growth.
There are generally three types of hand pruners: bypass pruners, anvil pruners and ratchet pruners. Bypass pruners use two curved blades that bypass each other in the same manner as a pair of scissors. One blade is sharpened on the outside edge and it slips by a thicker unsharpened blade. Anvil pruners have a single straight cutting blade that closes down on a flat edge or anvil. Anvil pruners have a slicing action similar to a knife against a cutting board and work well removing tough, dead wood. Ratchet pruners are similar to anvil pruners, but include a mechanism that performs the cutting action in stages to provide more leverage for the user.